assert() vs. enforce(), invariant() vs. ... ?

[Brian Rogoff]

On Saturday, 31 August 2013 at 21:30:40 UTC, Andrei Alexandrescu 
wrote:

>> http://stackoverflow.com/questions/4711309/meaning-of-scope-in-d-for-a-parameter
>
> That use will stay and is useful and uncontested.
>
> Andrei

Sure, but my complaint is that that useful style is cramped by 
the inability to have scope on *local variables*. I understand 
that scope on function parameters will stay. If you're saying 
that scope on local variables for delegates will stay, then 
disregard all I've written here, I'm happy! :-).

If you look at the code I posted, try removing scope from the 2-D 
integrate and from the local variable declarations in the main() 
function, and the program hits the GC, with the scopes, they 
don't. The problem occurs when I create the local variables to 
name an anonymous function. I tested this with Adam Ruppe's code 
which halts when the GC is called.

As I said, I'm not arguing for scope on objects, but for 
contrivances which allow me to program easily with downward 
funargs and not hit the GC. D goes further than most languages in 
this and it would be a shame if this capability is removed with 
no substitute.

For those who want to test on their systems, here are the trivial 
unitCircle and unitSphere I omitted.


float unitCircle(float x) {
   float x2 = x * x;
   if (x2 < 1.0) {
     return sqrt(1.0 - x2);
   } else {
     return 0.0;
   }
}

float unitSphere(float x, float y) {
   float sum = x*x + y*y;
   if (sum <= 1.0) {
     return sqrt(1.0 - sum);
   } else {
     return 0.0;
   }
}


-- Brian